Coach Michael Maguire has admitted South Sydney's decision to leave Greg Inglis on the field with a serious knee injury was wrong.

The Rabbitohs suffered a devastating blow to their 2017 NRL premiership chances when the champion fullback was ruled out for up to six months with an ACL injury.

Maguire stopped short of taking personal responsibility for leaving the clearly struggling Inglis - who played more than 50 minutes with the injury - on the park in Friday's NRL round one loss to Wests Tigers.

You might also like

He said the decision was made with consultation with medical staff.

"Hindsight is a great thing and obviously we put our hand up and we didn't get the call right," Maguire told News Corp Australia.

"Unfortunately it was the wrong call."

A "shattered" Maguire originally defended Souths' handling of the incident after the game, arguing Inglis himself was confident he could continue playing.

But the premiership-winning coach acknowledged coaching staff should have overruled their star player.

"When I got to him at halftime and I spoke to the doc he was determined to go back out and he thought it was going to be okay," Maguire said.

"Unfortunately, it didn't come across as any of us would have liked.

"Yes, we could have made a different call. But it just goes to show that he is a tough kid, and he wanted to do it for the club."